Other Treatments

Biological response modifier therapy, also called immunotherapy, uses the body's own immune system to fight cancer using natural or laboratory-developed factors. Drugs designed for such purposes used in combination with other treatments are showing promise in trials.

Monoclonal Antibodies

Monoclonal antibodies (MAbs) are designed in the laboratory to produce the same effects as natural antibodies and are exciting new weapons in the anticancer armament. They bind to specific proteins called antigens and make them vulnerable to attack by other factors in the immune system. Lymphomas carry antigens that provoke strong immune responses and so are believed to be particularly good candidates for MAb therapy.

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MAbs are called either unconjugated or conjugated, depending on how they are designed to destroy the cancer cell.

• Unconjugated monoclonal antibodies rely on a strong natural immune system. The antibody builds up at the tumor site until it is able to trigger an immune response against the cancer. A possible downside to this form is the potential development of tolerance to the antibody so that it loses its effectiveness. Rituximab is an unconjugated form and the first MAb to be approved for any cancer.
• Conjugated monoclonal antibodies are linked to a plant or bacterial toxin or radioisotope. The antibody specifically attacks the antigen on the lymphoma cell and the toxin or radioactive material from the isotope kills it.

Unconjugated MAbs (Rituximab and Others). Rituximab (Rituxan) was the first monoclonal antibody to be approved for any cancer. It is an unconjugated MAb that targets the CD-20 antigen, which is found on most B-cell lymphomas and normal mature B-cells (although not stem cells).